Sling suspension system for supporting the thumb of a patient after basal joint arthroplasty

ABSTRACT

A sling suspension system for supporting the thumb of a patient after basal joint arthroplasty, the sling suspension system comprising: an index metacarpal anchor, a thumb metacarpal anchor and a sling for securing the thumb metacarpal anchor to the index metacarpal anchor; the index metacarpal anchor comprising at least one bone-engaging element for engaging the index metacarpal and a sling-engaging element for capturing the sling to the index metacarpal anchor; the thumb metacarpal anchor comprising at least one bone-engaging element for engaging the thumb metacarpal and a sling-engaging element for capturing the sling to the thumb metacarpal anchor; and the sling comprising an elongated body having a first anchor-engaging element for securing the sling to the sling-engaging element of the index metacarpal anchor, and a second anchor-engaging element for securing the sling to the sling-engaging element of the thumb metacarpal anchor, wherein the second anchor-engaging element is adjustable.

REFERENCE TO PENDING PRIOR PATENT APPLICATIONS

This patent application:

(i) is a continuation-in-part of pending prior U.S. patent applicationSer. No. 12/577,057, filed Oct. 9, 2009 by Jeanne L. DelSignore forSURGICAL IMPLANTABLE STABILIZER SLING FOR BASAL JOINT ARTHROPLASTY(Attorney's Docket No. FENTON-8), which patent application claimsbenefit of prior U.S. Provisional Patent Application Ser. No.61/197,060, filed Oct. 23, 2008 by Jeanne Louise DelSignore for SURGICALIMPLANTABLE STABILIZER SLING FOR BASAL JOINT ARTHROPLASTY; and

(ii) claims benefit of pending prior U.S. Provisional Patent ApplicationSer. No. 61/927,309, filed Jan. 14, 2014 by CMC Group LLC and Izi Brukeret al. for BASAL THUMB ARTHRITIS SLING SYSTEM (Attorney's Docket No.FENTON-9 PROV).

The three (3) above-identified patent applications are herebyincorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to surgical methods and apparatus in general, andmore particularly to a novel sling suspension system for supporting thethumb of a patient after basal joint arthroplasty.

BACKGROUND OF THE INVENTION

Degenerative osteoarthritis of the first metacarpal joint of the thumb(sometimes referred to as “the basal joint”) is a common debilitatingcondition, especially in middle aged women. Investigations show that 25%of all women and 8% of all men in their fifties complain of pain in thebase of the thumb, secondary to basal joint osteoarthritis.

Basal joint arthritis can cause substantial pain, digit weakness andloss of functionality.

In severe cases of basal joint arthritis, basal joint reconstruction maybe required. In general, basal joint reconstruction involves trapezialexcision (“basal joint arthroplasty”), which is required for painrelief, and subsequent soft tissue reconstruction in order to re-createproper balance, alignment, longitudinal length and function to thethumb.

Unfortunately, this soft tissue reconstruction has historically involvedharvesting tendons which are subsequently transferred and redirected viadrill holes in the thumb metacarpal in order to restore proper balance,alignment, longitudinal length and function to the thumb. However, thismeans harvesting, and thereby sacrificing, all or some of a functioningtendon. In addition, the reconstruction typically requires temporarypinning, which can give rise to pin tract complications such asinfection, nerve damage and neuroma formation.

As a result, a new approach is needed for effecting basal jointreconstruction after performing basal joint arthroplasty in order toalleviate basal joint arthritis.

SUMMARY OF THE INVENTION

The present invention provides a new approach for effecting basal jointreconstruction after performing basal joint arthroplasty in order toalleviate basal joint arthritis.

More particularly, the present invention comprises the provision and useof a novel sling suspension system that joins the thumb metacarpal tothe index metacarpal so as to support the thumb of a patient after basaljoint arthroplasty. The present invention eliminates the specificcomplications and increased morbidity associated with tendon harvestingand transfer procedures and those procedures that require temporary pinfixation or drill holes for tendon or suture passage. The novel slingsuspension system of the present invention provides secure and stablesupport for the thumb of a patient after performing basal jointarthroplasty in order to alleviate basal joint arthritis, and isrelatively fast and simple to implement.

In one preferred form of the present invention, there is provided asling suspension system for supporting the thumb of a patient afterbasal joint arthroplasty, said sling suspension system comprising:

an index metacarpal anchor, a thumb metacarpal anchor and a sling forsecuring said thumb metacarpal anchor to said index metacarpal anchor;

said index metacarpal anchor comprising at least one bone-engagingelement for engaging the index metacarpal and a sling-engaging elementfor capturing said sling to said index metacarpal anchor;

said thumb metacarpal anchor comprising at least one bone-engagingelement for engaging the thumb metacarpal and a sling-engaging elementfor capturing said sling to said thumb metacarpal anchor; and

said sling comprising an elongated body having a first anchor-engagingelement for securing said sling to said sling-engaging element of saidindex metacarpal anchor, and a second anchor-engaging element forsecuring said sling to said sling-engaging element of said thumbmetacarpal anchor, wherein said second anchor-engaging element isadjustable.

In another preferred form of the present invention, there is provided amethod for supporting the thumb of a patient after basal jointarthroplasty, said method comprising:

securing a first end of a sling to an index metacarpal anchor;

positioning the index metacarpal anchor in the index metacarpal;

adjustably securing the second end of the sling to a thumb metacarpalanchor;

adjusting the securement of the second end of the sling to the thumbmetacarpal anchor so that the thumb metacarpal anchor is broughtadjacent to the thumb metacarpal; and

inserting the thumb metacarpal anchor into the thumb metacarpal so thatthe second end of the sling is fixedly secured to the thumb metacarpalanchor, whereby the sling fixedly connects the thumb metacarpal to theindex metacarpal.

In another preferred form of the present invention, there is provided amethod for alleviating basal joint arthritis, said method comprising:

excising the trapezium of a patient;

securing a first end of a sling to an index metacarpal anchor;

positioning the index metacarpal anchor in the index metacarpal;

adjustably securing the second end of the sling to a thumb metacarpalanchor;

adjusting the securement of the second end of the sling to the thumbmetacarpal anchor so that the thumb metacarpal anchor is broughtadjacent to the thumb metacarpal; and

inserting the thumb metacarpal anchor into the thumb metacarpal so thatthe second end of the sling is fixedly secured to the thumb metacarpalanchor, whereby the sling fixedly connects the thumb metacarpal to theindex metacarpal.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention will bemore fully disclosed or rendered obvious by the following detaileddescription of the preferred embodiments of the invention, which is tobe considered together with the accompanying drawings wherein likenumbers refer to like parts, and further wherein:

FIG. 1 is a schematic view showing the bone structure of the right handof a human;

FIG. 2 is a schematic view of a novel sling suspension system formed inaccordance with the present invention;

FIG. 3 is a schematic view showing an adjustable loop of the novel slingsuspension system shown in FIG. 2;

FIG. 4 is a schematic view showing the index metacarpal anchor and slingof the novel sling suspension system shown in FIG. 2 mounted to adriver;

FIG. 5 is a schematic view showing a basal joint reconstruction usingthe novel sling suspension system shown in FIG. 2; and

FIGS. 6-9 are schematic views showing alternative anchors which may beused in conjunction with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Looking first at FIG. 1, there is shown the right hand 5 of a human. Asseen in the figure, the basal joint 10 is formed at the junction of thethumb metacarpal 15 and the trapezium 20. Note also the location of theadjacent index metacarpal 25.

As noted above, many people suffer from significant basal jointarthritis and would benefit from basal joint reconstruction in order toalleviate the basal joint arthritis.

The present invention provides a new approach for effecting basal jointreconstruction after performing basal joint arthroplasty in order toalleviate basal joint arthritis.

More particularly, the present invention comprises the provision and useof a novel sling suspension system that joins the thumb metacarpal tothe index metacarpal so as to support the thumb of a patient after basaljoint arthroplasty. The present invention eliminates the specificcomplications and increased morbidity associated with tendon harvestingand transfer procedures and those procedures that require temporary pinfixation or drill holes for tendon or suture passage. The novel slingsuspension system of the present invention provides secure and stablesupport for the thumb of a patient after performing basal jointarthroplasty in order to alleviate basal joint arthritis, and isrelatively fast and simple to implement.

The Novel Sling Suspension System

Looking next at FIG. 2, there is shown a novel sling suspension system30 formed in accordance with the present invention. Sling suspensionsystem 30 generally comprises an index metacarpal anchor 35 fordeployment in index metacarpal 25, a thumb metacarpal anchor 40 fordeployment in thumb metacarpal 15, and a sling 45 for securing thumbmetacarpal anchor 40 to index metacarpal anchor 35, whereby to provide asling suspension system for supporting the thumb of a patient afterbasal joint arthroplasty has been performed in order to alleviate basaljoint arthritis.

Index metacarpal anchor 35 is intended to be deployed in (e.g., screwedinto or pushed into) a drill hole formed at or near the base of indexmetacarpal 25. To this end, index metacarpal anchor 35 comprises a body50 having at least one bone-engaging element 55 (e.g., screw threads,ribs, etc.) formed thereon for engaging index metacarpal 25. Indexmetacarpal anchor 35 further comprises a sling-engaging element 60(e.g., an eyelet) for capturing sling 45 to index metacarpal anchor 35.

Thumb metacarpal anchor 40 is intended to be deployed in (e.g., screwedinto or pushed into) a drill hole formed at or near the base of thumbmetacarpal 15. To this end, thumb metacarpal anchor 40 comprises a body65 having at least one bone-engaging element 70 (e.g., screw threads,ribs, etc.) formed thereon for engaging thumb metacarpal 15. Thumbmetacarpal anchor 40 further comprises a sling-engaging element 75(e.g., a groove or shoulder) for capturing sling 45 to thumb metacarpalanchor 40. In one form of the invention, sling-engaging element 75(e.g., the groove or shoulder) traverses 360 degrees around body 65 ofthumb metacarpal anchor 40.

Sling 45 secures thumb metacarpal anchor 40 to index metacarpal anchor35, whereby to provide a sling suspension system for supporting thethumb of a patient after basal joint arthroplasty has been performed inorder to alleviate basal joint arthritis. To this end, sling 45 comprisean elongated body having a first end 80 and a second end 85.

First end 80 includes an anchor-engaging element 90 (e.g., a knot) forsecuring sling 45 to sling-engaging element 60 of index metacarpalanchor 35 such that the sling is attached to the anchor.

Sling 45 also comprises an adjustable anchor-engaging element 95 forsecuring sling 45 to sling-engaging element 75 of thumb metacarpalanchor 40 such that the sling is attached to the anchor. In onepreferred form of the invention, adjustable anchor-engaging element 95comprises an adjustable loop 100 formed in sling 45 intermediate itsfirst end 80 and its second end 85. As seen in FIG. 3, adjustable loop100 is preferably formed by the sling being passed into itself at leastonce at a point 105 and emerging from itself at least once at a point110. As a result of this construction, when first end 80 of sling 45 isheld fixed (e.g., when first end 80 of sling 45 is secured to indexmetacarpal anchor 35 and index metacarpal anchor 35 is secured in indexmetacarpal 25), pulling on second end 85 of sling 45 will decrease thediameter of adjustable loop 100 (e.g., so as to secure sling 45 ingroove 75 of thumb metacarpal anchor 40, whereby to secure sling 45 tothumb metacarpal anchor 40).

The elongated body of sling 45 may comprise a filament (e.g., a suture),a rope, a web, a tape, etc., i.e., substantially any elongated structurewhich will suffice for the intended purpose, either man-made or biologic(e.g., crosslinked collagen, crosslinked hydrogel, chitosan, etc.), aswell as other biocompatible polymers or metals and/or compositestructures. In one preferred form of the invention, sling 45 comprises asuture. It should be appreciated that sling 45 can be a hollow or solidcore braided suture or a monofilament suture. It should also beappreciated that sling 45 should to be able to slide with respect toitself once it has been passed into itself, e.g., in the manner shown inFIG. 3. And it should be appreciated that sling 45 can be passed throughitself in such a way that points 105 and 110 lie on the same planeperpendicular to the primary axis of the sling, or the planes of entryand exit (i.e., points 105 and 110) can be circumferentially offset fromeach other.

Note also that adjustable loop 100 may be formed without passing sling45 back through itself, e.g., adjustable loop 45 may be formed by asliding knot or any other construction that allows the size ofadjustable loop 100 to be modified on demand.

If desired, multiple adjustable loops 100 may be provided along sling45, whereby to allow one anchor to mate with multiple adjustable loopson sling 45, or to allow multiple anchors to mate with sling 45 (e.g.,with each anchor engaging with one or more adjustable loops).

Looking now at FIG. 4, sling suspension system 30 preferably alsocomprises a driver 115 which may be used to set index metacarpal anchor35 into index metacarpal 25 and/or to set thumb metacarpal anchor 40into thumb metacarpal 15. To this end, driver 115 comprises a shaft 120having a drive feature at its distal end for engaging (i) a counterpartdrive feature of index metacarpal anchor 35, so as to enable driver 115to drive index metacarpal anchor 35 into index metacarpal 25, and/or(ii) a counterpart drive feature of thumb metacarpal anchor 40, so as toenable driver 115 to drive thumb metacarpal anchor 40 into thumbmetacarpal 15. A handle 125 is provided at the proximal end of shaft120.

In one preferred form of the invention, index metacarpal anchor 35 ispre-loaded on driver 115 at the time of system assembly and, afterdriver 115 has been used to set index metacarpal anchor 35 into indexmetacarpal 25, thumb metacarpal anchor 40 is loaded on driver 115 forsetting thumb metacarpal anchor 40 into thumb metacarpal 15. Where indexmetacarpal anchor 35 is pre-loaded onto driver 115 at the time of systemassembly, a stay line 130 can be used to secure index metacarpal anchor35 onto driver 115. In one preferred form of the invention, driver 115has a hollow construction such that sling 45 may be passed through shaft120 and handle 130 of driver 115 and emerge at the proximal end ofdriver 115.

Use of the Novel Sling Suspension System

Sling suspension system 30 may be used in the following manner tosupport the thumb of a patient after basal joint arthroplasty has beenperformed in order to alleviate basal joint arthritis.

1. Trapezium 20 is excised so as to alleviate the basal joint arthritis.See FIG. 5.

2. Index metacarpal 25 and thumb metacarpal 15 are prepared to receiveindex metacarpal anchor 35 and thumb metacarpal anchor 40, respectively.In one preferred form of the invention, a bone hole 135 is drilled intothe thumb side of index metacarpal 25, and a bone hole 140 is drilledinto the base of thumb metacarpal 15. Note that the space created by theexcised trapezium allows easy access to the base of thumb metacarpal 15and to index metacarpal 25.

3. First end 80 of sling 45 is attached to index metacarpal anchor 35using sling-engaging element 60 of index metacarpal anchor 35 andanchor-engaging element 90 of sling 45 (e.g., eyelet 60 and knot 90),and index metacarpal anchor 35 and sling 45 are mounted to driver 115.Alternatively, and more preferably, first end 80 of sling 45 ispre-mounted to index metacarpal anchor 35, and index metacarpal anchor35 and sling 45 are pre-mounted to driver 115 at the time of systemassembly.

4. Driver 115 is used to place index metacarpal anchor 35 into bone hole135 formed in index metacarpal 25.

5. Driver 115 is withdrawn from the deployed index metacarpal anchor 35,and thumb metacarpal anchor 40 is removably attached to driver 115 (oranother driver).

6. The free end of sling 45 is secured to thumb metacarpal anchor 40using sling-engaging element 75 of thumb metacarpal anchor 40 andadjustable anchor-engaging element 95 of sling 45. In one preferred formof the invention, this is effected by pulling second end 85 of sling 45so as to decrease the diameter of loop 100, whereby to secure adjustableloop 100 to groove 75 of thumb metacarpal anchor 40 (i.e., to cinch loop100 of sling 45 into groove 75 of index metacarpal anchor 40).

7. Thumb metacarpal anchor 40 is pulled towards index metacarpal 25(e.g., as the diameter of adjustable loop 100 is decreased).

8. When thumb metacarpal anchor 40 has been advanced to the appropriatelocation, thumb metacarpal anchor 40 is inserted into the base of thumbmetacarpal 15 while sling 45 is securely captured to thumb metacarpalanchor 40 (e.g., while adjustable loop 100 is securely captured ingroove 75 of thumb metacarpal anchor 40). Note that insertion of thumbmetacarpal anchor 35 into bone hole 140 in thumb metacarpal 15 capturesadjustable anchor-engaging element 95 (e.g., loop 100) of sling 45 inbone hole 140 so that adjustable anchor-engaging element 95 cannotdisengage from thumb metacarpal anchor 40 (a sling-to-anchor fixation).In addition, insertion of thumb metacarpal anchor 35 into bone hole 140in thumb metacarpal 15 captures portions of sling 45 between thumbmetacarpal anchor 40 and thumb metacarpal 15 with a binding interferencefit (a binding interference fit between anchor and bone). Thiscombination of sling fixations (i.e., the sling-to-anchor fixation andthe binding interference fit between anchor and bone) leads to a verystable fixation of sling 45 to thumb metacarpal 15, and hence to thecreation of a very stable suspension between index metacarpal 25 andthumb metacarpal 15.

9. Thumb metacarpal anchor 40 is inserted to a desired depth so as tocomplete the formation of a suspension sling between index metacarpal 25and thumb metacarpal 15. This suspension sling, which extends from indexmetacarpal anchor 35 (which is secured in index metacarpal 25) to thumbmetacarpal anchor 40 (which is secured in thumb metacarpal 15) is ableto support the thumb of a patient after basal joint arthroplasty hadbeen performed in order to alleviate basal joint arthritis. Note thatthumb metacarpal anchor 40 can be also be inserted on the far side ofthumb metacarpal 15 (i.e., the side facing away from index metacarpal25), thereby enabling sling 45 to traverse the entire base of thumbmetacarpal 15.

10. Second end 85 of sling 45 can then be cut with an appropriateinstrument if desired.

Additional Constructions

It is anticipated that index metacarpal anchor 35 and/or thumbmetacarpal anchor 40 may be replaced by other sling anchors. By way ofexample but not limitation, thumb metacarpal anchor 40 may be replacedby the thumb metacarpal anchor 40A shown in FIG. 6, or by the thumbmetacarpal anchor 40B shown in FIG. 7, or by the thumb metacarpal anchor40C shown in FIG. 8. Furthermore, thumb metacarpal anchor 40 could bereplaced by the thumb metacarpal anchor 40D shown in FIG. 9, whichcomprises the Pushlock™ suture anchor available from Arthrex, Inc. ofNaples, Fla., USA. With an anchor of this type, sling 45 can omit theaforementioned adjustable loop 100, and the second (free) end of sling45 can be passed through eyelet 75D formed in the anchor. In this formof the invention, sling 45 is captured to the bone by an interferencefit between the body of the anchor and the bone.

It is also anticipated that index metacarpal anchor 35 and thumbmetacarpal anchor 40 may be simultaneously loaded in the same driver,with index metacarpal anchor 35 being disposed distal to thumbmetacarpal anchor 40.

Furthermore, it is also contemplated that, if desired, the adjustabilityof the sling suspension may be provided on the index metacarpal side ofthe sling suspension rather than on the thumb metacarpal side of thesling suspension. Thus, in this alternative form of the invention, indexmetacarpal anchor 35 would be set in thumb metacarpal 15, and thumbmetacarpal anchor 40 would be set in index metacarpal 25, with the slingbeing tensioned on the index metacarpal side of the sling suspension.

In addition to the foregoing, it should also be appreciated that thepresent invention may be used in basal joint arthroplasties which may beconducted for purposes other than alleviating basal joint arthritis,e.g., such as in the case of disease and/or trauma.

Modifications

It is to be understood that the present invention is by no means limitedto the particular constructions herein disclosed and/or shown in thedrawings, but also comprises any modifications or equivalents within thescope of the invention.

1. A sling suspension system for supporting the thumb of a patient afterbasal joint arthroplasty, said sling suspension system comprising: anindex metacarpal anchor, a thumb metacarpal anchor and a sling forsecuring said thumb metacarpal anchor to said index metacarpal anchor;said index metacarpal anchor comprising at least one bone-engagingelement for engaging the index metacarpal and a sling-engaging elementfor capturing said sling to said index metacarpal anchor; said thumbmetacarpal anchor comprising at least one bone-engaging element forengaging the thumb metacarpal and a sling-engaging element for capturingsaid sling to said thumb metacarpal anchor; and said sling comprising anelongated body having a first anchor-engaging element for securing saidsling to said sling-engaging element of said index metacarpal anchor,and a second anchor-engaging element for securing said sling to saidsling-engaging element of said thumb metacarpal anchor, wherein saidsecond anchor-engaging element is adjustable.
 2. A sling suspensionsystem according to claim 1 wherein said second anchor-engaging elementis adjustable in length.
 3. A sling suspension system according to claim1 wherein said at least one bone-engaging element of said indexmetacarpal anchor comprises one from the group consisting of a screwthread and a rib.
 4. A sling suspension system according to claim 1wherein said sling-engaging element of said index metacarpal anchorcomprises an eyelet.
 5. A sling suspension system according to claim 1wherein said at least one bone-engaging element of said thumb metacarpalanchor comprises one from the group consisting of a screw thread and arib.
 6. A sling suspension system according to claim 1 wherein saidsling-engaging element of said thumb metacarpal anchor comprises ashoulder.
 7. A sling suspension system according to claim 6 wherein saidshoulder comprises part of a groove.
 8. A sling suspension systemaccording to claim 7 wherein said groove extends completely around saidthumb metacarpal anchor.
 9. A sling suspension system according to claim1 wherein said first anchor-engaging element comprises a knot.
 10. Asling suspension system according to claim 1 wherein said secondanchor-engaging element comprises an adjustable loop.
 11. A slingsuspension system according to claim 10 wherein said adjustable loop isformed by passing said sling through itself.
 12. A sling suspensionsystem according to claim 10 wherein said adjustable loop is formed by asliding knot.
 13. A sling suspension system according to claim 1 whereinsaid sling is in the form of a filament.
 14. A sling suspension systemaccording to claim 13 wherein said filament is in the form of a suture.15. A method for supporting the thumb of a patient after basal jointarthroplasty, said method comprising: securing a first end of a sling toan index metacarpal anchor; positioning the index metacarpal anchor inthe index metacarpal; adjustably securing the second end of the sling toa thumb metacarpal anchor; adjusting the securement of the second end ofthe sling to the thumb metacarpal anchor so that the thumb metacarpalanchor is brought adjacent to the thumb metacarpal; and inserting thethumb metacarpal anchor into the thumb metacarpal so that the second endof the sling is fixedly secured to the thumb metacarpal anchor, wherebythe sling fixedly connects the thumb metacarpal to the index metacarpal.16.-22. (canceled)
 23. A method for alleviating basal joint arthritis,said method comprising: excising the trapezium of a patient; securing afirst end of a sling to an index metacarpal anchor; positioning theindex metacarpal anchor in the index metacarpal; adjustably securing thesecond end of the sling to a thumb metacarpal anchor; adjusting thesecurement of the second end of the sling to the thumb metacarpal anchorso that the thumb metacarpal anchor is brought adjacent to the thumbmetacarpal; and inserting the thumb metacarpal anchor into the thumbmetacarpal so that the second end of the sling is fixedly secured to thethumb metacarpal anchor, whereby the sling fixedly connects the thumbmetacarpal to the index metacarpal.